An Orlando project to help disadvantaged youths is one of 18 winners of the 1988 Volunteer Action Awards to be presented by President Reagan at a White House luncheon June 10.

Operation Comeback, founded by William Prentiss, chairman of the Valencia Community College social sciences department, was chosen by The National Center, a private non-profit organization, and ACTION, the federal agency for voluntary service, as a winner this year.

Prentiss founded the program in 1976 to aid troubled youths, pairing them with college students who act as one-on-one counselors to establish friendships and provide guidance.

''Our kids do a great deal to help these youths, and they have done a great deal to help the city of Orlando,'' Prentiss said Sunday. ''Our kids have spent thousands of hours helping others.''

Winners of the Volunteer Action Awards were chosen from among 2,100 nominations submitted in 10 categories, including human services, education, health and the workplace.

In a printed statement issued by the White House, Reagan said, ''Throughout our history, Americans have reached out in service to others, near and far, and thereby strengthened their communities, our country and the entire world.''

Operation Comeback has served more than 1,300 troubled youngsters since it was founded to help youths referred by the Orange County Juvenile Court.

The program involves two kinds of volunteering.

Valencia students serve as counselors to the youths, who participate in community service projects. Many of the service projects involve youths participating in the Boy Scout troop and Boy Scout Explorer post sponsored by the college.

Most of the youngsters referred to the agency have been arrested or have experienced severe problems in the school system, Prentiss said. Some are on probation and have drug-abuse problems. About 95 percent are boys.

The counseling and Boy Scout programs lead them back to a healthier way of life, the White House statement said.